package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.bean.copier.CopyOptions;
import cn.hutool.core.util.RandomUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.LoginFormDTO;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.User;
import com.hmdp.mapper.UserMapper;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RegexUtils;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.connection.BitFieldSubCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import javax.servlet.http.HttpSession;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;
import static com.hmdp.utils.SystemConstants.USER_NICK_NAME_PREFIX;

@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Override
    public Result sendCode(String phone, HttpSession session) {
        // 1.校验手机号格式
        if(RegexUtils.isPhoneInvalid(phone)){
            return Result.fail("手机号格式错误!");
        }
        //2.符合，生成验证码
        String code = RandomUtil.randomNumbers(6);
        //3.保存验证码到 redis  (key:phone,value:code)
        stringRedisTemplate.opsForValue().set(LOGIN_CODE_KEY+phone,code,LOGIN_CODE_TTL, TimeUnit.MINUTES);
        //4.发送验证码
        log.debug("发送短信验证码成功");
        log.debug(code);
        //5.返回 ok
        return Result.ok();
    }

    @Override
    public Result login(LoginFormDTO loginForm, HttpSession session) {
        // 1. 校验手机号格式
        String phone = loginForm.getPhone();
        if (RegexUtils.isPhoneInvalid(phone)) {
            return Result.fail("手机号格式错误！");
        }

        // 2. 校验验证码（从 Redis 获取）
        String cacheCode = stringRedisTemplate.opsForValue().get(LOGIN_CODE_KEY + phone);
        String inputCode = loginForm.getCode();
        if (cacheCode == null || !cacheCode.equals(inputCode)) {
            return Result.fail("验证码错误或已过期");
        }

        // 3. 根据手机号查询用户（不存在则创建）
        User user = query().eq("phone", phone).one();
        if (user == null) {
            user = createUserWithPhone(phone);
        }

        // 4. 生成登录 token，转换用户信息为 Redis Hash 格式
        String token = UUID.randomUUID().toString();
        UserDTO userDTO = BeanUtil.copyProperties(user, UserDTO.class);
        Map<String, Object> userMap = BeanUtil.beanToMap(
                userDTO,
                new HashMap<>(),
                CopyOptions.create()
                        .setIgnoreNullValue(true)
                        .setFieldValueEditor((fieldName, fieldValue) ->
                                fieldValue != null ? fieldValue.toString() : "")
        );

        try {
            stringRedisTemplate.opsForHash().putAll(LOGIN_USER_KEY + token, userMap);
            stringRedisTemplate.expire(LOGIN_USER_KEY + token, LOGIN_USER_TTL, TimeUnit.MINUTES);
        } catch (Exception e) {
            stringRedisTemplate.delete(LOGIN_USER_KEY + token);
            log.error("用户登录：Redis 存储失败", e);
            return Result.fail("登录失败，请重试");
        }

        // 7. 返回登录成功的 token
        log.debug("用户登录成功");
        return Result.ok(token);
    }

    @Override
    public Result sign() {
        Long userId = UserHolder.getUser().getId();
        LocalDateTime now = LocalDateTime.now();
        String keySuffix = now.format(DateTimeFormatter.ofPattern(":yyyyMM"));
        String key=USER_SIGN_KEY+userId+keySuffix;
        int dayOfMonth = now.getDayOfMonth();
        // 写入 redis   setbit key offset 1
        stringRedisTemplate.opsForValue().setBit(key,dayOfMonth-1,true);
        return Result.ok();
    }

    //统计从今天往前的连续签到次数
    @Override
    public Result signCount() {
        Long userId = UserHolder.getUser().getId();
        LocalDateTime now = LocalDateTime.now();
        String keySuffix = now.format(DateTimeFormatter.ofPattern(":yyyyMM"));
        String key=USER_SIGN_KEY+userId+keySuffix;
        int dayOfMonth = now.getDayOfMonth();
        // 获取本月截止今天为止的所有签到记录，返回的是一个十进制数字 （共dayOfMonth位）
        // bitfield sign:1:202509 get u14 0
        List<Long> result = stringRedisTemplate.opsForValue().bitField(
                key, BitFieldSubCommands.create()
                        .get(BitFieldSubCommands.BitFieldType.unsigned(dayOfMonth))
                        .valueAt(0)
        );
        if(result==null || result.isEmpty()){
            return Result.ok(0);
        }
        Long num = result.get(0);
        if(num==null || num==0){
            return Result.ok(0);
        }
        // 循环遍历，与 1 做与运算，得到数字的最后一个 bit 位置
        int count=0;
        while (true){
            if((num & 1)==0){
                // 该 bit 位为0，未签到，结束
                break;
            }else {
                // 不为0，已签到，计数器+1
                count++;
            }
            // 数字右移 1 位，用前一个 bit位 与1运算
            num >>>=1;
        }
        return Result.ok(count);
    }

    private User createUserWithPhone(String phone) {
        User user = new User();
        user.setPhone(phone);
        user.setNickName(USER_NICK_NAME_PREFIX+RandomUtil.randomString(10));
        save(user);   // mybatisplus 自带的
        return user;
    }
}
